Research Of High Repetition Space Debris Laser Ranging System

With the increase in the amount of space debris, space debris poses a seriousthreat to spacecraft operation and human space activities. Space debris monitoringand early warning is widely concerned by researchers all around the world. Spacedebris laser ranging (DLR) could be used not only in monitoring and improving thedebris orbit accuracy but also in calibration for other monitoring method. It issignificant to the study on space debris.This paper is based on Changchun60cm aperture laser ranging system, aimingat a series of problems such as space debris objects’ angular rate, prediction accuracy,signal identification, to establish space debris laser ranging (DLR) system with highrepetition rate, high precision, high sensitivity and high automation, realizedeffective observation at last. It is the first research on high repetition DLR in China.The system has achieved nearly200passes, with the minimum RCS1.2m2, bestminimum range precision of21.5cm, in which8twilight passes. The maincontributions of this dissertation can be summarized as follows:(1) Calculation and analysis of DLR system detection ability, in order to providethe basis for the design of high repetition DLR system.(2) Developed high repetition real-time control subsystem, established highaccuracy independent timing system, export high frequency firing and range-gatesignal, to ensure real-time, stable, reliable data transmission and synchronous observation.(3) According to the analysis of two line elements (TLE) and the SGP4model,the space debris object selection criteria is given. By introducing the concept ofreturn index, established the target database, to improve the detection rate of success.(4) Applied image processing technique to extract edge information gatheredfrom the real-time CCD image, so as to exactly calculate the laser beam tip deviationfrom FOV center, corrected the real time laser beam pointing.(5) For the problem of weak space debris diffuse reflection, the high sensitivity,high quantum efficiency, low noise, single photon Geiger-mode APD detector wasdeveloped to receive weak photon returns.(6) The multiple filtering algorithm was improved, in order to solve the highrepetition frequency DLR data extraction problem, so as to realize data identificationunder low SNR.In short, high repletion DLR will play an important role in the field of spacedebris monitoring and warning.